Files (.c and .h) containing low level GPIO drivers (HAL layer) for
Freescale was added to platforms/cortexM4/K60_120/. This files belong to
KSDK (externals/ksdk)

Also an include path to inc/device is added to
externals/platforms/make/Makefile, in order to include the correct .h
Freescale files (without changing any .c or .h from ksdk)
Merge branch 'master' of https://github.com/ciaa/Firmware into 0.3.0_rc1
improve doc for release 0.3.0